Notes on the Northern Gulf of Mexico Occurrence of Sagitta friderici Ritter-Zahony (Chaetognatha)

The neritic chaetognath Sagitta friderici Ritter-Zahony, 1911 was identified in plankton samples from the northern Gulf of Mexico in June 1974. Specimens analyzed from two groups of adults ranged from 6 to 13.7 mm long. Meristic values did not appear to be a function of body length except for individuals in the 12.4 to 13.7 mm range that had larger numbers of hooks and teeth. Adults of Sagitta friderici and the closely related S. tenuis Conant, 1896 were compared and found to be distinguishable chiefly by (1) the number of ova per unit length of the ovary, and (2) the arrangement of ova within the ovary. The TC values were highly variable and overlapping, thus casting doubt on the taxonomic importance of that characteristic. Sagitta friderici was abundant in inshore continental shelf waters where the salinity and temperature ranged from 24.9 to 33.9 ppt and 23.0 to 30.3°C, respectively. The failure to determine ecological boundaries between S. friderici and S. tenuis revealed a need for more intensive sampling in coastal regions of the Gulf of Mexico

Observations on Chaetognath Distributions in the Northeastern Gulf of Mexico During the Summer of 1974

The chaetognath population was studied from zooplankton samples collected at twelve stations in the northeastern Gulf of Mexico in June 1974. Quantitative analysis of six stations revealed a large inshore population composed largely of juveniles and neritic species in the upper strata, and a progressively smaller and more evenly dispersed assemblage composed largely of oceanic, stenohaline species at stations further offshore. The high percentage of juveniles in surface samples evidenced an early-summer spawning peak for the population as a whole. Overlying low salinity water throughout the study area was characterized by the presence of two neritic species, Sagitta tenuis and S. friderici, in surface samples, while an underlying high salinity intrusion over the continental shelf was denoted by the submerged occurrence of stenohaline species. Fourteen species were grouped into three ecological categories denoting degrees of tolerance to environmental change: (1) neritic - Sagitta friderici, S. tenuis, S. helenae, S. hispida, (2) mixed water - S. enflata, S. minima, S. serratodentata, Pterosagitta draco, Krohnitta pacifica, and (3) oceanic - S. hexaptera, S. bipunctata, K. subtilis, S. decipiens, S. lyra

An Illustrated Key to the Chaetognatha of the Northern Gulf of Mexico with Notes on their Distribution

A key is provided to facilitate the identification of 24 species in nine genera of Chaetognatha occurring in the northem Gulf of Mexico. Included are the deep-water species, Eukrohnia proboscidea, E. calliops, Mesosagitta sibogae, and Sagitta megalophthalma, all recent additions to the known fauna of the region. Meristic data, brief descriptions, ecological notes, Gulf of Mexico records, and illustrations are also presented

First Recorded Observance of the Dinoflagellate Prorocentrum minimum (Pavillard) Schiller 1933 in Mississippi Sound and Adjacent Waters

The present paper documents the occurrence of the dinoflagellate Prorocentrum minimum in Mississippi Sound and adjacent coastal waters. Outbreaks of discolored water are attributed to blooms of P. minimum in February 1977 and in January and February 1981. Data are presented on the seasonality of the organism in St. Louis Bay. Observations on water appearance and a descriptive analysis of the cells are presented for the 1981 blooms

Aricidea (Allia) bryani, a New Species of Polychaete (Polychaeta: Paraonidae) from the Northern Gulf of Mexico

Aricidea bryani, a new species of polychaete (Polychaeta: Paraonidae) belonging to the subgenus Allia Strelzov 1973, is described from shallow subtidal sediments along the northern shore of Mississippi Sound, an estuary of the northern Gulf of Mexico. The new species is distinguished from other members of the subgenus by the presence of tuberculate neuropodial lobes in the anterior 15-20 setigers, a cirriform median antenna that extends posteriorly to setiger three, and by modified neuropodial setae that are abruptly tapered at mid-length, but lack terminal aristae

Notes on Some Chaetognaths from Pine Cay, Turks and Caicos Islands (British West Indies)

Seven species of planktonic Chaetognatha - Ferosagitta hispida, Flaccisagitta enflata, F. hexaptera, Krohnitta pacifica, Sagitta bipunctata, Serratosagitta serratodentata, and Pterosagitta draco - were present in plankton samples collected in waters north of Pine Cay, Turks and Caicos Islands, British West Indies. In addition, the epibenthic species Spadella cephaloptera, Paraspadella nana, and P. schizoptera were present, the latter two species associated mainly with shallow clumps of the coralline alga, Neogoniolithon sp., and with sponge-algal communities. One specimen of S. cephaloptera was collected at 35 m from a sand bottom north of the fringing reef adjacent to Pine Cay. Meristic data for F. hispida and for the three epibenthic species are provided

Notes on the Northern Gulf of Mexico Occurrence of Sagitta friderici Ritter-Zahony (Chaetognatha)

The neritic chaetognath Sagitta friderici Ritter-Zahony, 1911 was identified in plankton samples from the northern Gulf of Mexico in June 1974. Specimens analyzed from two groups of adults ranged from 6 to 13.7 mm long. Meristic values did not appear to be a function of body length except for individuals in the 12.4 to 13.7 mm range that had larger numbers of hooks and teeth. Adults of Sagitta friderici and the closely related S. tenuis Conant, 1896 were compared and found to be distinguishable chiefly by (1) the number of ova per unit length of the ovary, and (2) the arrangement of ova within the ovary. The TC values were highly variable and overlapping, thus casting doubt on the taxonomic importance of that characteristic. Sagitta friderici was abundant in inshore continental shelf waters where the salinity and temperature ranged from 24.9 to 33.9 ppt and 23.0 to 30.3°C, respectively. The failure to determine ecological boundaries between S. friderici and S. tenuis revealed a need for more intensive sampling in coastal regions of the Gulf of Mexico

Notes on Some Chaetognaths from Pine Cay, Turks and Caicos Islands (British West Indies)

Seven species of planktonic Chaetognatha - Ferosagitta hispida, Flaccisagitta enflata, F. hexaptera, Krohnitta pacifica, Sagitta bipunctata, Serratosagitta serratodentata, and Pterosagitta draco - were present in plankton samples collected in waters north of Pine Cay, Turks and Caicos Islands, British West Indies. In addition, the epibenthic species Spadella cephaloptera, Paraspadella nana, and P. schizoptera were present, the latter two species associated mainly with shallow clumps of the coralline alga, Neogoniolithon sp., and with sponge-algal communities. One specimen of S. cephaloptera was collected at 35 m from a sand bottom north of the fringing reef adjacent to Pine Cay. Meristic data for F. hispida and for the three epibenthic species are provided

Aricidea (Allia) bryani, a New Species of Polychaete (Polychaeta: Paraonidae) from the Northern Gulf of Mexico

Aricidea bryani, a new species of polychaete (Polychaeta: Paraonidae) belonging to the subgenus Allia Strelzov 1973, is described from shallow subtidal sediments along the northern shore of Mississippi Sound, an estuary of the northern Gulf of Mexico. The new species is distinguished from other members of the subgenus by the presence of tuberculate neuropodial lobes in the anterior 15-20 setigers, a cirriform median antenna that extends posteriorly to setiger three, and by modified neuropodial setae that are abruptly tapered at mid-length, but lack terminal aristae

First Recorded Observance of the Dinoflagellate Prorocentrum minimum (Pavillard) Schiller 1933 in Mississippi Sound and Adjacent Waters

The present paper documents the occurrence of the dinoflagellate Prorocentrum minimum in Mississippi Sound and adjacent coastal waters. Outbreaks of discolored water are attributed to blooms of P. minimum in February 1977 and in January and February 1981. Data are presented on the seasonality of the organism in St. Louis Bay. Observations on water appearance and a descriptive analysis of the cells are presented for the 1981 blooms